Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVstudent » Sat May 31, 2014 11:49 pm

Lets cut to the chase.
1. Bubka 's height of COM is 1.21m above the runway at take-off.
2. Trandenkov's height of COM is 1.28m above the runway at take-off.
The taller of the two vaulters had the higher centre of mass and hence greater gravitational potential energy at take-off.

Similar calculation leads to the result that at COM peak height with respect to the bar height Trandenkov for his 5.80m bar clearance had a bar to peak height differential of 0.065m (6.5cm or just a "tad" over 2.5 inches).

Bubka's had a bar height to COM peak height of 0.19m ( a 7.5 inch COM - Bar height differential on this jump!). In another competition the peak COM height was 6.50m for Bubka!

In this competition with Trandenkov, Bubka had less Total Energy on their respective jumps. Yes, Bubuka will have had a greater grip length on the pole but a 20cms difference in their bar heights would, I guess be sufficient to cancel the grip differential effect!

As to their relative efficiency, go figure chaps and good luck.

When and if you do, look carefully at the "Pole contribution Optimization effects diagram 3) I posted. That's just a request. It may give pause for though as to whether a better efficiency index might be watts / kg power per unit vaulter body mass thereby allowing work rate to be considered. It also should give you some vital clues as to the type of training types and power training Lavillenie has been using.

However I really don't believe we shall get much further in all this so I, for one reader, am not interested to know what spin you want to put on your efforts in regard to the above.

The your physics are better than mine stuff is taking us all away from the kernel of the efficiencies arguments. I am moving on.

Oh, and surprise, surprise Decamouse shows some pictures (Brilliant effort Decamouse) and PVdaddy agrees Lavillenie has been improving!

Willriefer, instead of trying to use the "ships passing in the night argument" and a total misrepresentation of the above to make this false conclusion in regard to the real data obtained from two vaulters you identified for comparison

willrieffer wrote: This would seem to lead to a very odd conclusion. That building muscle mass over CoM, simply raising the CoM in this way, would give the vaulter an advantage? Really? Is that really what I'm thinking? OR again maybe everything is way way more complex than that...


can you, or other readers, confirm or deny that the evidence I put up for examination supports my assertion that since 2009 Lavillenie has improved upon his drop leg technique in the first support phase of the pole vault by May 2014?

Decamouse 's evidence has convinced me I am not delusional. So readers shatter my illusions!

If my illusion is just that, I will happily concede that Willreifer's conceptual analysis of the take-off and techniques of swing control in the first phase of pole vault as exemplified by Dossevi is worthy of serious reconsideration.

To me Dossovi's technique is a distant echo to the French approach to pole vaulting of the 1970's through to about 1996! Nothing new or radical.

Since that epoch there has been a steady sea change in their approach with their elite vaulters as the grip lengths on the pole have had to become longer and the inexorable rise in technique development demand to be able to use stiffer poles.

Renaud Lavillenie is the epitome of this steady evolution and yet there is still room for him to improve his technical efficiency even though he is a fabulous pole vaulter and worthy World Indoor Record Holder at 6.16m. Let us rejoice and celebrate his achievement but also refrain from searching for "radical" or "mysterious hitherto unknown or unknowable use of the laws of physics" to account for his achievement.

The answers are all there in the evidence from the past and the practical expression of that knowledge revealed by the superb vaulting of some elite women and male pole vaulters around today.

"I hear, I look, I see, I do and then I understand that I must Listen, Hear, See Anew and Redo and discover my belief in my understanding was ill founded and so the action cycle must repeat itself until the performance reflects enlightenment" may be a mantra worthy of all pole vaulters and coaches. In the end what is initially mysterious and complex reveals itself to be simple but only through the effort of personal action can this be found.

I rest my case with respect to Lavillenie and the efficiency issue. Without the data the exercise is going to continue to be chasing "Will O'the Wisps!" (Pun intended but without any malice!)
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby KirkB » Sun Jun 01, 2014 12:24 am

PVstudent wrote: ... can you, or other readers, confirm or deny that the evidence I put up for examination supports my assertion that since 2009 Lavillenie has improved upon his drop leg technique in the first support phase of the pole vault by May 2014?

Decamouse 's evidence has convinced me I am not delusional. So readers shatter my illusions! ...

I'm good with that, and ready to give it a rest. Like 3P0, I'm getting tired of reading all this stuff, and sorting out the wheat from the chaff! :D

Some of it's been very interesting and enlightening, but some of it is just circular arguments, and (it seems to me) a bit of a p**sing contest. Everyone wants to get the last word in edgewise. Are we done? :confused:

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVstudent » Sun Jun 01, 2014 2:44 am

Yes Kirk I don't want this contest to be all "p##$ and wind".

At the risk of evoking St Elmo's Fire ( a phenomenon known to exist!) but merely seeking whether you are agnostic on the matter what is your interpretation of the evidence on Lavillenie that I put up. The qualitative decision is very simple. Yes he has improved in the specifics I dentify or No he hasn't.

The evoking of ST Elmo's fire is meant as Irony!

St. Elmo's fire is named after [b]St. Erasmus of Formia (also called St. Elmo, one of the two Italian names for St. Erasmus, the other being St. Erasmo), the patron saint of sailors. The phenomenon sometimes appeared on ships at sea during thunderstorms and was regarded by sailors with religious awe for its glowing ball of light, accounting for the name.Because it is a sign of electricity in the air, which can interfere with compass readings, some sailors may have regarded it as an omen of bad luck and stormy weather.[/b]

Lets hope our compass bearings on this topic return to distilling what the take home messages might be for coaches and pole vaulters should be.

I will address the request from Willreifer to discuss the pendular motion of the vaulter on the physics critique thread that he abandoned and where he did not in my view respond to the specific problems that I asked him to address in regard to a statics analysis of the take-off before proceeding to a Dynamics analysis.

Over to Willreifer in the physics critique thread.

I am not an engineer or physicist nor claim to be but the analysis can give very good approximations using first order linear differential equations to describe both the kinematics and kinetics of pendular type swinging by pole vaulters.

There is no need for more complex or esoteric prognostication on the matter.

So far as I can tell from Will's efforts in regard to the gravity vector he has nothing to say that is not obvious and very well known and accepted by coaches namely that the vaulter's weight force (which must act vertically downward at all times throughout the vault) exerts a tangential ,and normal to the tangential force, that assist or resists the swing action of the vaulter. We all know this fact.

When I get around to my response I will point readers to some more recent work from a decathlon pole vaulter with a PhD in Physics who is also an academic and biomechanic whose work Willriefer appears to have no knowledge of. If he is aware, then I suspect he has not understood the "gravitas" and esteem in which this person's work is viewed.

So Kirk and others, are you all agnostics and will you leave me with my illusions?
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby Decamouse » Sun Jun 01, 2014 5:19 am

These are from RL WR vault - not best angles but shows there is decent knee drive - "in my opinion"
RL2 Page 001.jpg
not great angle or distance but look at bottom frame -
RL2 Page 001.jpg (37.37 KiB) Viewed 3359 times
RL2 Page 002a.jpg
RL2 Page 002a.jpg (21.3 KiB) Viewed 3359 times
RL2 Page 002b.jpg
RL2 Page 002b.jpg (23.93 KiB) Viewed 3359 times
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby Decamouse » Sun Jun 01, 2014 5:25 am

Know those crops (last out of Steve Chappell video) show knee drive -- what is optimum? Angle also creates some deception - also would need high speed so not to miss the max point -- I have also attached this showing a youngster - taken at 90 to runway almost perfectly aligned at takeoff point - best perspective -- would you consider this good drive?
Wyatt2.jpg
Wyatt2.jpg (26.5 KiB) Viewed 3358 times


Regarding did I test poles - yes did some for about eight years -- http://www.decamouse.com has a page that is all about poles and vaulting -

Are there differences between the two vaulters - yes - I say on RL world record everything worked - run - takeoff - swing - correct pole - good standards placement - and the bar was set at the WR height -- seen vaulter's with more pronounced knee drop (Tim Lobinger - 6m man) -
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Sun Jun 01, 2014 9:48 am

PVstudent wrote:Lets cut to the chase.
1. Bubka 's height of COM is 1.21m above the runway at take-off.
2. Trandenkov's height of COM is 1.28m above the runway at take-off.
The taller of the two vaulters had the higher centre of mass and hence greater gravitational potential energy at take-off.


Do you have a starting Kinetic Energy state for them at all? Were their take off speeds measured here in particular where there is evidence of a very high differential? I asked for it, as its relative, and if it was about it would seem to be a simple cut and past for you.

And you make no mention about the difficulty in reducing to its elements the generative process of angular velocity. Bubka is a tremendous problem for this analysis because of his well document high vertical take off velocity, which, because of the nature of the KE equation makes for too good a logical case he had the highest take off energy, with a further idea that it could be used to overcome swing elements.

This kind of stuff is why we've both come to the conclusion that its a waste of time to deal with each other...and a great bulk of your posts are Sophistry.

FWIW It could be angle, but PVStudent's time view of Lavilenie's WR jump seems to show his lead foot actually lower than his trail, not something most vaulters do...and, well, all vaulters are going to show some variance over time. Is it noteworthy, or style? Intent change or variance?

I have been thinking about some stuff. One of the things that comes out of the discussions is the nature of late PE change. A high late PE rate change indicates vertical velocity which is what the vaulter is trying to get to. A part of it comes simply from the pole. One of the things is I've talked about high path and low path. We are talking about the PE curve. IF its rise is somehow forestalled, then if the vaulter makes the vault it is almost necessary that they have a higher rate of PE change at the end of the vault. They have higher vertical velocity. This morning in thinking on things I had an intuitive sense I can prove all of this by math and logic, but that the problem is going to take a while, and that I might need some help. My son has a friend who is a math/science wiz, and I think I'm going to see if I can get his help opinion as he's studying this stuff now, and I've been years from it. The thing is you can't just take the low path. Lets say two vaulters, same size and take off energy. Now one works the low path and one the high path. IF they are on the same pole, one or the other could have a problem. High path can stall out. Low, get too far forward and shoot up under the bar. But, if our low path guy can use a stiffer pole, and still attain a lower path, I think he gets a vertical velocity advantage, which is what we are looking for...


Not particularly anything new again. I have to figure out some calculus stuff relative to the PE curve and its area. We'll see if I can get anything out of it. But we see again and again poles are important, but an intentional attitude toward bending poles in coaching technique renders some idea that the nature of the relation of bend to the PE curve is somehow unimportant...

"throw the sailors overboard....overboard..."

Will

P.S. edit

My own cut to the chase calculations...

KE = 1/2 m v squared

Bubka = 1/2 x 80kg x 9.94 m/s x 9.94m/s = 3952j
Tradenkov = 1/2 x 78kg x 9.47m/s x 9.47m/s = 3498j

v values and weights are those printed on this site in 6m club table

1. Bubka 's height of COM is 1.21m above the runway at take-off.
2. Trandenkov's height of COM is 1.28m above the runway at take-off.

PE = mgh

Bubka = 80kg x 9.8 m/s x 1.21m = 948.64j
Tradenkov = 78kg x 9.8 m/s x 1.28m = 978.43j

PE + KE

Bubka = 948.64j + 3952j = 4900.64j
Tradenkov = 3498j + 978.43j = 4476.43j

Difference
Bubka + 424.21j

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Sun Jun 01, 2014 12:05 pm

I am trying my best to analyze Lavellenies vault from a purely unbiased Scientific perspective. I clearly do not see nearly the amount of knee drive in these Stills of RL WR vault(Decamouse made every attempt to capture them at peak height) as compared to Bubka. Are my eyes deceiving me? Is it merely the angle? PLease others do tell?
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby Decamouse » Sun Jun 01, 2014 1:34 pm

Does he drive it to same extent as Bubka did on some vault - no do not think so -- does he reach the same point as many other vaulters - different question - just like speeds used in the KE equations -- if they are not at the instant the pole tip hits the box (if vaulter is not 100% free take-off) is it somewhat misleading -- now if you take-off out -- they if further complicates it since the COM has already started raising before the tip hits the box -- but again 5m out speed is an indicator -- not totally accurate - does anyone know if they had runway measurements for approach speeds on WR vault?
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby willrieffer » Sun Jun 01, 2014 3:43 pm

Decamouse wrote:Does he drive it to same extent as Bubka did on some vault - no do not think so -- does he reach the same point as many other vaulters - different question - just like speeds used in the KE equations -- if they are not at the instant the pole tip hits the box (if vaulter is not 100% free take-off) is it somewhat misleading -- now if you take-off out -- they if further complicates it since the COM has already started raising before the tip hits the box -- but again 5m out speed is an indicator -- not totally accurate - does anyone know if they had runway measurements for approach speeds on WR vault?


One source is the IAAF data which I was pointed to which showed Bubka at from approximately 9.5 m/s on some jumps to approaching the high 9.8 m/s range to possibly 9.9 m/s range. This somewhat supports the PVP 6m chart number. Plus there is just all the other evidence of his speed. We're going way way back, but I remember T&F News doing an article on him making a possible Decathlon attempt*. Some things I remember, possibly not completely accurately, was that he had a 5th place in the 100 at the Euro Juniors and a PR 100m time of 10.1 sec. 10.3 sec seems to be the number to come up most often. Still very fast. He was fast. Its been measured and its rather visible. So why is there an effort to keep slowing him down? Hmmmm...

The IAAF data also shows he's accelerating through the measurements near take off...

The results as a whole IMHO show he was one of, it not the most energetic, take off vaulters of all time and that's without assessing take off angle or the pre take off effect where the idea there is that he was one of the more efficient vaulters at the method.

Where Tradenkov's numbers come from sans this site, I don't know. If its an average, I'd probably put him capable of numbers like I proposed for Lavillenie in part coming from analysis of the IAAF data. If its an average you can probably expect a spread from about +/- .1 m/s to .2 m/s. That would put him capable of approaching 9.6 m/s to perhaps 9.7 m/s or so as an estimate.

Will

* Their conclusion was that if he could get 95% values on his known PR he would have shattered the WR by somewhere around 1000pts. By the article he had marks in of the 10 events. I remember the HJ and LJ numbers were both highly remarkable...

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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Sun Jun 01, 2014 7:03 pm

Decamouse, Thank-You for the Stills of Lavellenie. Note the wide hand spacing. Does this allow him to stay further behind the pole earlier? Is this Petrov?

I would say the 3rd Photo down captures what I would describe as the completion of penetration (Which I call the completion of Vaulter/Pole system loading). This is the end of penetration and the beginning of his swing. I believe he lowers his lead knee as he's going through penetration. Note the lower knee position in this still from the one above. Note the elbow is still slightly bent to allow top hand loading.I believe this also is the point he begins to maximally extend his top hand and keeps it there all the way through his swing to his ball tuck.

Note the bottom hand elbow is not even close to being severely bent or the hand even close to being extended back directly above the head as Bubka's is during his completion of penetration! Is this Petrov?

Note how much more below the pole Lavellenie already is at this moment in time and how much lower his COG and swing path starts, as compared to Bubka! Is this Petrov?

He does not have to extend his bottom hand far at all to fully lower his COG through his swing as Bubksa does, therefore he captures the low COG position much, much sooner then Bubka! This, along with a lower take off leg and flatter take-off (less vertical component) has been my most major point from the very beginning.

I believe his early low COG bends the pole more and earlier, which effectively shortens the chord earlier, while at the same time he experiences less braking loss when transitioning from the run to the jump, therefore preserves more vertical velocity from his slower run-up going into take-off. I believe that this is what allows the shorter, slower vaulter to rotate the same hand grip height as the taller, faster Bubka to vertical!

I believe that from this very low COG fully extended (Long lever) swing path position, he immediately and as forcibly as possible begins his quasi double leg (Is this Petrov?) swing. Like the LONG metronome, it appears slow at first (He is braking that long lever into the pole causing it to bend more as he is moving forward, but he is quasi leg swinging as fast as he can!) and when he immediately tucks (Is this Petrov?) while pulling through the shoulders into that continually top hand leaning position (always keeps the pressure on the top hand and this is Petrov) he immediately and rapidly accelerates as the lever is so shortened into a compact tucked ball (Is this Petrov?) with both knees fully packed at each side of his body and the bottom of his feet pointing skyward.

Now comes the fastest point in his entire swing! Now he is ready to take back all that energy he has so brilliantly worked into the pole. No, in fact he ready to also add some of his own on top. From that tightly compact ball, he is able to immediately, simultaneously and forcible extend both feet into the air with their full range of motion. He is already vertical, with both legs perfectly lined and extended side be side. He is now ready to receive the poles energy through his bottom hand and in fact adds more as he pushes the bottom hand downward toward the pit. This strong gripping action on the pole insures the full transfer of energy to his body. He adds the last share of energy with a strong top hand push for his final domination of gravity.

There you have it at least 5 differences I see in the Lavellenie Method of Pole vaulting. Is this Petrov?
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Sun Jun 01, 2014 10:42 pm

So in my opinion, at least during this WR vault, other than the fact that Lavellenie maintains continuous pressure on the top hand after take off and through his swing, his position and mechanics going into and after take-off and his position and mechanics through his penetration and low path swing are not Petrov.

The main area that I believe is Petrov is his high pole Cary and drop during run up. He is also attempting and sometime achieving a free takeoff per Petrov. But, even here his plant mechanic are not the same, as his hand spacing is wider, with his bottom coming up from behind the hip in a round house fashion further away from his temple and not directly up from the hip along his side and temple. Now I see at least 6 thing that Make this Lavellenie Method, not Petrov.
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Re: Swing Efficiency Comparison: Bubka, Tradenkov, Lavillenie

Unread postby PVDaddy » Sun Jun 01, 2014 11:25 pm

Will:
Some want to keep reducing the differences of Bubka and Lavillenie. Why? The differences in swing mechanics are different than just the leg drop. It's left arm use. It's the tuck and its nature and why he needs to use it at all versus the "straight leg" method. Or, its a different swing with different actions on the pole. Is it better? I don't know for sure, but I think it is...can I prove it. Dunno


Well I for one am confident we have, in our simple, straight forward, Physics, swing efficiency calculation. You just cannot deny the lower runway velocity (lets be conservative and say its only .35 M/S) deficit Lavellenie has to deal with and at an exponent of 2! You also can not deny the lower COG starting point or the lower plant angle as well? Need I say more?

I am also confident that PVstudent has some other small conciderations such as Pole recoil efficiencies we could consider and I would be delighted if he would provide the data, as it is entirely possible we could do the physics and show the math?
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